EXCHANGE 


A  Study  of  1  -  Hydroxylamino-Anthraquinone 
and  Some  of  Its  Derivatives 


WALTER  H.  BEISLER 


A.  Study  of  1  -  Hydroxylamino-Anthraquinone 
and  Some  of  Its  Derivatives 


A  DISSERTATION 

/ 

PRESENTED  TO  THE 

FACULTY  OF  PRINCETON  UNIVERSITY 

IN  CANDIDACY  FOR  THE  DEGREE 

OF  DOCTOR  OF  PHILOSOPHY 

BY 
WALTER  H.  BEISLER 


EASTON,  PA.: 

ESCHENBACH  PRINTING  COMPANY 
1922 


-It 


[Reprinted  from  the  Journal  of  the  American  Chemical  Society, 
Vol.  XLIV,  No.  10.     October,  1922.] 


A  STUDY  OF  1-HYDROXYLAMINO-ANTHRAQUINONE  AND  SOME 
OF  ITS  DERIVATIVES 

Introduction 

The  0-aryl-hydroxylamines  as  a  class  are  fairly  well  known.  They  are 
usually  prepared  by  the  partial  reduction  of  the  corresponding  nitro  com- 
pounds. In  some  cases  they  appear  among  the  products  obtained  when 
primary  amines  are  oxidized  and  the  oxidation  is  controlled  with  proper 
care.  The  first  member  of  the  series,  /3-phenylhydroxylamine,  which  may 
be  considered  as  a  typical  compound  of  this  class,  is  of  historical  im- 
portance because  of  the  difficulties  early  investigators  encountered  in 
their  attempts  to  prepare  it.  In  the  presence  of  mineral  acids  of  proper 
concentration  it  is  readily  transformed  into  p-aminophenol,  and  it  was 
this  compound  which  was  usually  obtained  when  j8-phenylhydroxylamine 
might  have  been  expected.  It  was  not  until  1894,  that  Bamberger1 
and  Wohl,2  working  independently,  succeeded  in  preparing  /3-phenylhy- 
droxylamine  by  the  reduction  of  nitrobenzene  in  a  neutral  medium.  This 
may  be  accomplished  by  the  interaction  of  aluminum  amalgam  with  an 
ether  solution  of  nitrobenzene,  or  by  the  action  of  zinc  dust  upon  nitro- 
benzene suspended  in  a  water  solution  of  some  neutral  salt,  such  as  ammon- 
ium chloride  or  calcium  chloride.3 

Although  anthraquinone  derivatives  in  general  have  been  studied  in- 
tensely during  the  past  50  years,  very  little  attention  has  been  paid  to  the 
hydroxylamine  derivatives,  so  that  the  literature  on  the  subject  is  very 
meager.  Schmidt  and  Gattermann4  prepared  the  1,5-dihydroxylamino- 
anthraquinone  by  the  reduction  of  the  1,5-dinitro  compound  with  a  solu- 
tion of  sodium  stannite.  This  compound  crystallized  in  red-brown  needles, 
which  dissolved  in  alkalies  with  a  characteristic  blue-green  color.  No 
melting  point  could  be  determined  because  of  decomposition.  Hot,  cone, 
sulfuric  acid  converts  the  dihydroxylamino  derivative  into  1,5-diamino- 
4,8-dihydroxy-anthraquinone.  The  dihydroxylamine  derivative  showed 
weak  base-forming  properties;  it  dissolved  in  hydrochloric  acid  to  form  a 
solution  which  was  practically  colorless  and  from  which  it  could  be  re- 
covered unchanged  by  the  addition  of  water.  When  an  alkaline  solution 

1  Bamberger,  Ber.,  27,  1347  (1894). 

2  Wohl,  ibid.,  27,  1432  (1894). 

3  Wislicenus,  ibid.,  29,  494  (1896). 

4  Schmidt  and  Gattermann,  ibid.t  29, 2934  (1896). 


1  -HYDROXYLAMINO-ANTHRAQUINONE 


2297 


of  it  was  shaken  wth  benzoyl  chloride,  a  dibenzoyl  derivative  melting  at 
188°,  and  a  tribenzoyl  derivative  melting  at  228°  were  obtained. 

In  a  similar  way,  the  same  investigators  obtained  1-hydroxylamino- 
anthraquinone.  It  was  transformed  into  l-amino-4-hydroxy-anthra- 
quinone  when  it  was  heated  with  cone,  sulfuric  acid. 
.  -A  little  later,  .Wacker5  found  that  1-nitro-anthraquinone  could  be 
reduced  to  the  hydroxylamine  derivative  by  sodium  hydrogen  sulfide, 
the  cathode  action  of  the  electric  current,  and  best,  by  glucose  and  alkalies. 
He  also  prepared  the  nitroso-sulfonic  acid  derivative  of  anthraquinone 
by  sulfpnation  of  the  hydroxylamine  derivative  and  oxidation  of  the 
sulfonate  in  alkaline  solution  by  means  of  potassium  ferricyanide,  or  by 
chromic  acid.  He  described  the  nitroso-sulfonic  acid  as  a  yellow-red 
powder. 

The  deep  color  of  the  hydroxylamine  derivatives  of  anthraquinone  and 
the  remarkable  change  in  color  produced  when  these  compounds  are  dis- 
solved in  alkalies  are  properties  characteristic  only  of  this  particular  class 
of  0-hydroxylamine  derivatives;  it  is  natural  to  infer  that  these  unusual 
properties  undoubtedly  develop  through  some  influence  exerted  by  the 
anthraquinone  nucleus.  The  present  work  was  begun  with  the  intention 
of  studying  the  monohydroxylamine  derivative  obtained  from  1-nitro- 
anthraquinone  in  more  detail  than  had  previously  been  done.  A  study 
of  this  kind  might  be  expected  to  bring  to  light  other  irregularities  in  the 
behavior  of  this  compound,  which  could  be  traced  to  some  influence  exerted 
by  the  anthraquinone  nucleus.  In  the  light  of  the  theories  of  color,  the 
explanation  for  the  sharp  difference  in  the  colors  of  the  free  hydroxylamine 
derivative  and  its  sodium  salt  should  be  sought  for  in  differences  in  structure. 
The  proximity  of  the  carbonyl  group  to  the  hydroxylamino  group  makes 
such  an  interpretation  seem  very  satisfactory, — theoretically,  at  least. 
If  we  assume  that  the  free  hydroxylamino  derivative  has  the  usual  struc- 
ture formula  (II)  assigned  to  such  compounds,  its  sodium  salt  may  be 

Derived  from  at  least  two  other  structures  (I  and  III). 

/H 

OH    N— OH  O       N<  o  — N  — H 

X)H 


.     '        i  -_ 

I  II  in 

Formula  I  is  in  accord  with  the  theory  suggested  ,by  Georgievics6  to  explain 

5  Wacker,  Ber.,  35,  666,  3922  (1902). 

6  Georgievics,  "Die  Beziehungen  zwischetf  Farbe  und  Konstitution bei  Farbstoffe," 
Zurich,  1921,  p.  89. 


2298 

the  color  of  alizarin  (Formula  IV)  and  other  hydroxy-anthraquinone 
salts.  He  assumes  that  the  formation  of  an  ortho-qumoid  ring  which  is 
favored  by  the  influence  of  the  hydroxy  group  in  Position  1,  produces 
red  or  blue  colors  (Formula  V) ;  and  that  the  formation  of  a  ^ara-quinoid 
ring  which  may  be  attributed  to  the  predominating  influence  of  the  hy- 
droxy group  in  Position  2,  produces  yellow  or  brown  colors.  In  a  some- 
what similar  fashion,  Scholl  and  Zinke7  and  O.  Baudisch8  describe  the  salts 
and  lakes  of  alizarin  and  other  hydroxy-anthraquinones  as  Inner  complex 
compounds  in  which  the  partial  valences  indicated  by  dotted  lines  are 
variable  in  their  values.  (Formula  VI). 

O       OH  OH    O  O Me.. 

I 


|-°H 


O 

Alizarin  Salts  of  Alizarin 

(orange-red)  (purple-blue) 

IV  V  VI 

The  theory  of  Georgevics  was  criticised  by  Meek  and  Watson9  because, 
as  they  stated,  it  was  not  entirely  in  harmony  with  the  facts.  They  sug- 
gested the  following  generalizations  which  they  claim  are  applicable  not 
only  to  poly  hydroxy-anthraquinone,  but  to  other  classes  of  dyes. 

"(a)  Two  hydroxyl  groups  in  one  benzene  nucleus  in  the  ortho  or  para  position  with 
respect  to  one  another  are  necessary  to  produce  a  deep  (red,  violet,  or  blue)  color. 

(b)  The  color  is  still  further  deepened  if  both  benzene  nuclei  contain  pairs  of 
hydroxyl  groups  in  the  o-  or  p-  position  to  one  another. 

(c)  Three  hydroxyl  groups  in  the  1:2:4  positions  in  one  benzene  nucleus  produce  a 
deeper  color  than  a  pair  of  hydroxyl  groups  in  the  o-  and  p-  positions. 

(d)  Three  hydroxyl  groups  in  the  1:2:3  positions  in  one  benzene  nucleus  produce  a 
brown  color." 

It  is  the  opinion  of  the  present  writers  that  the  correct  explanation  for 
the  colors  of  the  hydroxylamine  derivative  of  anthraquinone  and  its 
salt  will  not  be  definitely  established  until  the  investigation  is  carried 
considerably  beyond  the  scope  of  the  present  work. 

Properties  of  Pure  1-Nitro-anthraquinone 

Since  1-hydroxylamino-anthraquinone  has  no  definite  melting  point  by 
which  its  degree  of  purity  may  be  checked,  and  since  it  is  very  difficult 
to  purify  it  by  the  usual  methods  of  crystallization,  it  became  obvious  that 

7  Scholl  and  Zinke,  Ber.,  51,  1419  (1918). 

8  Baudisch,  ibid.t  52,  146  (1919). 

9  Meek  and  Watson,  /.  Chem.  Soc.,  109,  557  (1916).     "Colour  in  Relation  to  Chem- 
ical Constitution,"  E.  R-  Watson,  Longmans,  Green  and  Co.,  1921,  p.  101. 


1-HYDROXYLAMINO-ANTHRAQUINONK  2299 

the  1-nitro-anthraquinone  used  in  this  investigation  should  be  as  pure  as 
possible.  There  are  many  methods  of  preparation  given  in  the  literature,  l° 
most  of  which  depend  on  the  action  of  strong  nitric  acid  (sp.  gr.  1.4-1.5), 
or  "mixed  acids"  on  anthraquinone.  Most  of  these  methods  were  tried 
in  this  laboratory  and  found  unsatisfactory  for  the  preparation  of  pure 
1-nitro-anthraquinone.  They  invariably  produced  mixtures  of  unchanged 
anthraquinone,  1-nitro-anthraquinone  and  dinitro-anthraquinone,  which 
were  exceedingly  difficult  to  separate  completely  by  any  method  at  our 
disposal. 

In  this  connection,  it  is  interesting  to  note  that  the  melting  point  of 
pure  1-nitro-anthraquinone  was  in  dispute  during  the  years  1882—1897. 
Boettger  and  Peterson,  in  1873,  prepared  it  by  heating  anthraquinone  with 
cone,  nitric  acid  (sp.  gr.  1.48-1.50).  They  found  the  melting  point  to  be 
230  °.  On  reduction  with  sodium  hydrogen  sulfide,  it  gave  an  amine  which 
melted  at  256°.  In  1882,  Roemer,  by  treating  anthraquinone  with  a 
mixture  of  nitric  acid  and  sulfuric  acid,  obtained  a  1-nitro  compound  melt- 
ing at  220°  which  he  thought  to  be  different  from  that  obtained  by  Boettger 
and  Peterson  because  of  the  difference  in  melting  points.  Graebe  and 
Liebermann11  cleared  up  the  confusion  by  proving  that  both  compounds 
were  identical  because  they  gave  the  same  amine  which  melted,  after 
purification,  at  242-243°  (corr.).  They  also  found  that  the  corrected 
melting  point  of  1-nitro-anthraquinone  was  228°.  However,  there  still 
seems  to  be  some  question  concerning  the  true  melting  point  of  1-nitro- 
anthraquinone,  since  Barnett  in  his  recent  book  on  "Anthracene  and 
Anthraquinone"10  uses  the  melting  point  found  by  Roemer,  namely, 
220°. 

In  order  to  avoid  further  confusion  from  this  source,  we  have  determined 
the  melting  points  of  1-nitro-anthraquinone  and  the  amino  derivative, 
after  obtaining  both  of  these  compounds  in  a  high  state  of  purity.  Our 
values  for  these  compounds  are  higher  than  those  given  by  Graebe  and 
Liebermann,  namely,  1-nitro  anthraquinone,  232.5-233.5°  (corr.),  and 
1-amino-anthraquinone,  252-253° (corr.).12  The  lower  melting  points 
usually  found  for  1-nitro-anthraquinone  are  undoubtedly  explained  by 
the  difficulty  of  separating  it  from  impurities.  On  the  other  hand,  amino- 
anthraquinone  is  remarkable  for  the  fact  that  its  melting  point  seems  to 

10  Boettger  and  Peterson,  Ann.,  166,  147  (1873).     Claus  and  Hertel,  Ber.,   14, 
977  (1881).     Roemer,  ibid.,  15,  1787  (1882).     Liebermann,  ibid.,  16,  54  (1883).    Miiller, 
Z.  Elektrochem.,  7,  797  (1901).     Lauth,  Compt.  rend.,  137,  661   (1903).      Ullmann  and 
von  der  Schalls,  Ann.,  388,  203(1912).     Barnett,  "Anthracene  and  Anthraquinone, "  D. 
Van  Nostrand  Co.,  1922,  p.  167. 

11  Graebe  and  Liebermann,  Ber.,  30,  1117  (1897). 

12  The  corrected  melting  points  were  determined  with  a  short-stem  thermometer 
with  the  mercury  column  completely  immersed  in  the  bath.     The  melting  points,  as 
found  by  the  usual  method  (using  a  long-stem  thermometer)  were  as  follows:    1-nitro- 
anthraquinone,  226-227°;  1-amino-anthraquinone,  245-246°. 


2300 

be  very  little  affected  by  the  impurities  formed  when  an  impure  sample 
of  nitro-anthraquinone  is  reduced.  A  sample  of  very  impure  1 -nitro- 
anthraquinone  melting  at  190-220°  on  reduction  with  sodium  sulfide  gave 
a  crude  amine  which  melted  at  243—245°  and,  therefore,  led  us  to  believe 
that  it  was  practically  pure.  However,  when  the  amine  was  recrystallized, 
we  found  that  it  contained  a  large  amount  of  unchanged  anthraquinone 
and  probably  some  diamines. 

The  phthalic  acid  synthesis,  which  may  be  used  for  preparing  anthra- 
quinone, many  of  its  homologs  and  certain  of  its  derivatives,  does  not  seem 
to  be  applicable  for  the  preparation  of  1 -nitro-anthraquinone.  It  might 
be  expected  that  1-nitro-phthalic  anhydride  would  condense  with  benzene 
in  the  presence  of  aluminum  chloride  to  give  a  nitrobenzoyl-benzoic  acid 
which,  on  treatment  with  dehydrating  agents,  would  form  1 -nitro-anthra- 
quinone, just  as  phthalic  acid  and  benzene  react  to  give  benzoyl-benzoic 
acid  from  which  anthraquinone  is  obtained  without  difficulty. 

N02  9  N02   ° 

NO2 


OH 


All  attempts  to  bring  about  this  synthesis  by  the  usual  methods  failed 
completely.  The  condensation  product  was  always  dark  colored  material, 
which  could  not  be  purified  or  converted  into  1 -nitro-anthraquinone. 

A  study  of  the  reaction  between  1-nitro-phthalic  anhydride  and  benzene 
in  the  presence  of  aluminum  chloride  was  made  recently  by  Lawrance.13 
He  succeeded  in  isolating  the  two  possible  condensation  products,  2- 
benzoyl-3-nitrobenzoic  acid  and  2-nitro-6-benzoylbenzoic  acid,  but  the 
yields  were  very  poor  (about  10%  of  the  amount  calculated)  and  55-60% 
of  the  anhydride  was  recovered  unchanged.  Apparently  no  attempt  was 
made  by  Lawrance  to  close  the  ring  so  as  to  form  nitro-anthraquinone. 

Practically  all  of  the  1 -nitro-anthraquinone  used  in  our  work  was 
prepared  by  a  method  devised  in  this  laboratory  after  considerable  ex- 
perimental work.  It  consists  in  heating  anthraquinone  with  fuming  nitric 
acid  (sp.  gr.  1.60)  and  crystallizing  the  crude  product  successively  from 
glacial  acetic  acid,  from  toluene  and,  finally,  from  acetone.  This  method 
produces  a  very  pure  product.  The  details  are  given  in  the  experimental 
part. 

Conversion    of    1 -Nitro-anthraquinone    into    1-Hydroxylamino-anthra- 

quinone 

The  methods  of  Schmidt  and  Gattermann   (with  sodium  stannite) 
13  Lawrance,  J.  £m.  Chem.  Soc.,  42,  1871  (1920). 


1-HYDROXYIvAMINO-ANTHRAQUINONB  2301 

and  of  Wacker  (with  glucose  and  sodium  hydroxide)  for  the  reduction  of 
1-nitro-anthraquinone  to  the  hydroxylamine  derivative  are  difficult  to 
carry  out  successfully.  The  conditions  under  which  these  reactions  pro- 
ceed, namely,  in  the  presence  of  a  warm  solution  of  an  alkali,  are  quite 
favorable  to  further  reduction  to  the  amine.  We  found  that  reduction 
is  best  brought  about  by  the  action  of  hydrogen  sulfide  upon  a  suspension 
of  the  nitro  compound  in  pyridine  at  0°.  Under  these  conditions  there 
is  very  little,  if  any,  tendency  for  further  reduction  to  the  amine.  The 
hydroxylamine  derivative  separated  as  a  dark  colored  powder  which 
crystallized  from  chloroform  in  the  form  of  small  maroon  colored  needles, 
and  from  methanol  in  clusters  of  the  same  color. 

For  the  sake  of  comparison  and  contrast  with  the  results  of  the  present 
work,  some  of  the  characteristic  properties  of  /3-phenylhydroxylamine 
may  be  mentioned.  It  is  a  colorless  solid  melting  at  81  °.  In  its  chemical 
properties  it  plays  the  dual  role  of  a  reducing  agent  and  an  oxidizing  agent. 
Chromic  acid  readily  oxidizes  it  to  nitrosobenzene.  It  reduces 
Fehling's  solution  and  an  ammoniacal  solution  of  silver  nitrate. 
Furthermore,  in  the  presence  of  an  alkali  it  absorbs  oxygen  from  the  air 
and  is  converted  into  various  products,  among  them  nitrobenzene  accom- 
panied by  some  hydrogen  peroxide.  Even  a  neutral  solution  of  it  in  water 
takes  up  oxygen  from  the  air;  nitroso-benzene  and  an  equivalent  amount 
of  hydrogen  peroxide  are  the  primary  products.  In  the  absence  of  air, 
an  alkaline  solution  undergoes  intramolecular  oxidation  and  reduction, 
and  nitrosobenzene  and  aniline  are  formed  primarily.  It  condenses, 
even  at  room  temperature,  with  benzaldehyde  to  form  a  N-substituted 
aldoxime.14  When  hydrogen  chloride  is  passed  through  its  solution  in 
ether,  /3-phenylhydroxylamine  hydrochloride  separates  as  colorless  crys- 
tals. A  solution  of  sodium  nitrite  at  0°  converts  the  hydrochloride  to 
/3-phenylnitroso-hydroxylamme.15  It  reacts  with  diazo-benzene  to  form 
phenyl-diazo-hydroxylaminobenzene. ' 6 

Unlike  0-phenylhydroxylarnine,  which  is  a  colorless  solid  with  a  definite 
melting  point,  1-hydroxylamino-anthraquinone  crystallizes  in  dark  maroon 
colored  crystals,  which  decompose  without  showing  a  definite  melting 
point.  The  group,  -NHOH,  acts,  in  this  case,  as  an  auxochromic  group ; 
a  distinct  change  in  color  from  anthraquinone  itself  results  from  its  sub- 
stitution. Furthermore,  when  this  compound  is  converted  into  its  sul- 
fonic  acid  derivative,  it  dyes  wool  and  silk  without  a  mordant,  producing 
shades  of  red-brown  which  are  comparatively  stable  to  light.  A  sample  of 
wool  dyed  with  this  material  showed  no  change  after  being  exposed  to  the 
sun  for  2  weeks.  One  of  the  most  striking  properties  of  this  hydroxylamine 

14  Bamberger,  Ber.,  27,  1556  (1894). 

15  Ref.  15,  p.  1553. 

16  Ref.  3,  p.  1434.     Bamberger,  Ber..  20,  102  (1896). 


2302 

derivative  is  the  pronounced  change  in  color  which  results  when  it  is  treated 
with  alkalies;  deep  blue-green  solutions  are  formed  from  which  the  original 
material  may  be  precipitated  by  the  addition  of  acid, — provided  the  alka- 
line solution  is  not  exposed  too  long  to  the  air.  If  air  is  passed  through  the 
alkaline  solution,  1-nitroso-anthraquinone  is  precipitated  and  some  hy- 
drogen peroxide  is  formed. 

The  potassium  salt  of  1-hydroxylamino-anthraquinone  was  isolated 
by  adding  the  calculated  amount  of  potassium  ethylate  to  an  acetone 
solution  at  0°.  It  proved  to  be  a  very  unstable  substance;  it  is  oxidized 
on  exposure  to  the  air.  When  it  was  washed  with  ether  in  a  suction 
funnel,  sufficient  heat  was  generated  to  cause  a  considerable  amount  of 
the  ether  to  vaporize.  The  salt,  when  freshly  prepared  is  dark  green  in 
color,  and  it  dissolves  with  some  difficulty  in  warm  water,  but  more  readily 
in  a  mixture  of  acetone  and  water  to  give  the  characteristic  blue-green 
solution.  After  exposure  to  air  for  some  time,  it  becomes  red-brown  in 
color  because  of  oxidation  to  the  nitroso  compound  which  may  be  extracted 
from  the  residue. 

The  hydroxylamine  derivative  is  a  fairly  strong  reducing  agent,  since 
it  reduces  an  ammoniacal  solution  of  silver  nitrate  almost  instantly  in  the 
cold,  but  it  has  very  little  effect  on  Fehling's  solution.  It  forms  a  substi- 
tuted urea  derivative  when  it  is  boiled  with  a  solution  of  phenyl-isocyanate 
in  dry  toluene. 
C«H4(CO)2C,H3-NHOH  +  OCN-C,H*  =  C^4(CO)2C,H,-N(OH)-CO-NHC6Hfi. 

The  hydroxylamine  derivative  is  remarkably  stable  toward  aldehydes. 
It  does  not  combine  with  acetaldehyde  even  when  the  mixture  is  heated 
in  a  sealed  tube  at  100°.  It  may  be  dissolved  in  boiling  benzaldehyde  and 
crystallized  from  it  without  undergoing  any  change.  It  shows  some  base- 
forming  properties,  since  it  dissolves  in  strong  acids,  but  no  hydrochloride 
could  be  isolated  by  the  usual  method.  When  it  was  treated  with  nitrous 
acid  in  the  presence  of  a  mineral  acid,  no  nitroso-hydroxylamine  could  be 
isolated,  although  /3-phenylhydroxylamine  undergoes  this  reaction  readily. 
It  reacts  with  benzoyl  chloride  or  with  acetyl  chloride  in  alkaline  solution, 
presumably  to  form  the  benzoyl  or  the  acetyl  derivative.  We  were  unable 
to  isolate  a  pure  material  in  either  case,  so  the  products  were  not  analyzed. 
When  diazobenzene  reacts  with  the  hydroxylamine  derivative  in  alkaline 
solution,  the  blue-green  color  is  destroyed  and  a  red-brown  powder  is 
formed  which  melts  with  decomposition  at  about  140°.  We  were  unable 
to  find  a  suitable  solvent  for  purifying  this  material,  so  it  was  not  analyzed. 

Experimental  Part 
The  Preparation  of  Anthraqutnone  from  Anthracene  by  Sulfuric  Acid  and  Sodium 

Bichromate 

In  order  to  prepare  pure  1-nitro-anthraquinone  by  the  method  described,  it  is 
necessary  to  employ  a  good  grade  of  anthraquinone.     The  usual  laboratory  method  for 


1-HYDROXYLAMINO-ANTHRAQUINONB  2303 

oxidizing  anthracene  to  anthraquinone  consists  in  treating  anthracene  in  glacial  acetic 
acid  with  chromic  acid.  We  have  found  that  the  commercial  method,  which  employs 
sulfuric  acid  and  sodium  dichromate  hi  water  solution,  when  properly  applied,  gave  a 
better  yield  and  was  generally  more  satisfactory.  This  method  is  a  modification  of  the 
method  taken  from  patent  literature  and  given  by  Weyl.17 

Seventy-five  g.  of  anthracene  (m.  p.  205-209  °)  was  suspended  in  300  cc.  of  boiling 
water  in  a  2-liter  beaker.  It  is  necessary  to  use  a  fairly  large  container  and  an  efficient 
mechanical  stirring  device  to  prevent  loss  from  foaming.  To  this  mixture  was  added  a 
solution  of  180  g.  of  technical  sodium  dichromate  dissolved  in  a  small  amount  of  hot 
water.  While  the  solution  boiled  and  was  stirred  rapidly,  a  mixture  of  225  g.  of  cone, 
sulfuric  acid  and  150  g.  of  water  was  added  through  a  funnel  drop  by  drop.  After  all  the 
acid  had  been  introduced,  the  mixture  was  boiled  and  stirred  for  about  1  hour.  The 
product  was  allowed  to  cool  partially,  and  was  filtered  with  the  aid  of  a  pump.  The  pre- 
cipitate was  washed  with  boiling  water  until  it  was  free  from  chromium  salts.  The  crude 
product  melted  at  274-276°;  yield,  98%.  It  was  dissolved  in  three  times  its  weight 
of  aniline,  from  which  it  crystallized  in  the  form  of  light  yellow  needles.  This  material 
was  collected  on  glass  wool  in  a  Hirsch  funnel,  washed  first  with  a  little  aniline,  and  then 
the  aniline  was  removed  with  methyl  alcohol.  Yield,  80-85%;  m.  p.,  277-278°. 

NOTES. — 1.  Excessive  foaming,  which  sometimes  takes  place,  may  be  overcome 
if  the  flame  is  removed  and  the  flow  of  acid  is  stopped  for  a  moment.  If  this  fails,  a 
little  cold  water  from  a  wash  bottle  should  be  poured  down  the  inside  of  the  beaker. 

2.  Anthraquinone  separates  from  aniline  as  a  semi-solid  mass  which  should  be 
broken  up  with  a  glass  rod  to  form  a  thin  paste. 

3.  The  crude  anthraquinone  as  obtained  above  may  be  purified  further  by  heating 
it  with  100%  sulfuric  acid  at  120 °  for  2  hours.     This  solution,  still  hot  (80-90 °),  is  poured 
into  a  large  volume  of  boiling  water,  and  the  precipitated  anthraquinone  is  collected. 
The  precipitate  should  be  washed  with  hot  water,  then  withahotdil.  solution  of  sodium 
hydroxide  and,  finally,  with  hot  water.     It  is  very  light  gray  in  color.     It  crystallizes 
from  chloroform  in  silky,  hair-like  crystals  almost  white  in  color.     The  yield  and  melting 
point  are  practically  the  same  as  before. 

The  Preparation  of  Pure  1-Nitro-anthraquinone 

Thirty-five  g.  of  finely  powdered  anthraquinone  was  suspended  in  280  g.  of  fuming 
nitric  acid  (sp.  gr.  1.60)  in  a  600cc.  flask.  The  mixture  was  boiled  gently  on  a  water- 
bath  for  exactly  40  minutes;  during  this  time  it  was  shaken  occasionally  to  insure  com- 
plete solution.  The  initial  temperature  of  the  water-bath  was  55°;  it  was  gradually 
increased  to  70-75°.  When  the  solution  had  cooled  partially,  it  was  poured  slowly  into 
about  3  liters  of  cold  water  which  was  stirred.  The  nitro-anthraquinone  was  washed 
several  times  by  decantation,  collected  and  washed  thoroughly  with  boiling  water. 
Yield,  40  g.;  m.  p.  190-225°.  This  crude  product  was  refluxed  with  800  cc.  of  glacial 
acetic  acid  and  filtered  from  insoluble  matter.  Most  of  the  1-nitro  compound  separated 
as  the  solution  cooled.  Yield,  25-30  g. ;  m.  p.,  215-220  °.  It  was  crystallized  from  700  cc. 
of  toluene.  Yield,  20-25  g.;  m.  p.,  220-222°.  This  product  was  finally  crystallized 
from  about  1200  cc.  of  acetone,  from  which  it  separated  in  large,  brilliant,  amber-colored, 
tetragonal  prisms.  Yield,  15-18  g.  (about  40%);  m.  p.  226-227°;  m.  p.  (corr.),  232.5- 
233.5°. 

Analysis.™  Subs.,  0.4093:  N,  20.8  cc.  (26°,  766  mm.).  Calc.:  N,  5.54  Found: 
5.67 


17  Weyl,  "Die  Methoden  der  Organischen  Chemie,"  vol.  2,  p.  962.     References  to 
the  patent  literature  are  given  here  also. 

18  The  nitrogen  in  each  case  was  collected  over  KOH  solution  made  by  dissolving 
30  g.  of  KOH  in  100  cc.  of  water. 


2304 

1-Amino-anthraquinone,  by  the  Reduction  of  the  Nitro  Compound19 
Two  g.  of  this  pure  sample  of  iTiritro-anthraquinone  was  ground  in  a  mortar  with 
4  g.  of  potassium  sulfide  and  sufficient  water  to  make  a  thin  paste.  This  paste,  which 
was  dark  green  in  color,  was  poured  into  200  cc.  of  boiling  water,  and  the  mixture  was 
boiled  for  about  1  hour.  The  amino  compound  was  collected  and  washed  thoroughly 
with  boiling  water.  It  was  a  brick-red  powder,  with  a  bronze-like  luster.  It  crystallized 
from  absolute  alcohol  in  beautiful,  long,  bright  red  needles  with  a  distinct  greenish 
sheen.  Yield,  2  g.;  m  p.,  245-246°;  m.  p.,  (corr.)  252-253°. 

Analysis.  Subs,  0.3575:  N,  19.6  cc.  (18°,  756  mm.).  Calc.:  N,  6.28.  Found: 
6.29. 

1-Hydroxylamino-anthraquinone,  by  the  Reduction  of  the  Nitro  Compound 
with  Pyridine  and  Hydrogen  Sulfide 

Two  hundred  cc.  of  pyridine  (technical)  was  placed  in  a  500cc.  Erlenmeyer  flask 
and  saturated  with  dry  hydrogen  sulfide  at  0°.  To  the  ice-cold  solution,  8  g.  of  very 
finely  powdered  1-nitro-anthraquinone  was  added  in  small  portions  while  the  flask  was 
shaken  vigorously.  The  nitro  compound  dissolved  quite  readily,  and  was  reduced 
to  the  hydroxylamino  compound  which  formed  a  solution  intensely  red  in  color.  After 
all  of  the  nitro  compound  except  a  slight  residue  was  dissolved,  the  solution  was  poured 
into  about  2  liters  of  cold  water  which  was  stirred  to  complete  the  precipitation.  The 
hydroxylamino  derivative  separated  as  a  dark  maroon  colored  precipitate.  It  was 
collected  rapidly  and  washed  with  hot  water  to  remove  pyridine.  The  precipitate  was 
transferred  to  a  700cc.  flask  and  suspended  in  a  mixture  of  100  cc.  of  acetone  and  300  cc. 
of  water  at  40-60°.  Forty  cc.  of  a  1 : 3  solution  of  sodium  hydroxide  was  added  and  the 
flask  was  shaken  vigorously  for  a  few  moments  to  dissolve  the  hydroxylamine  as  the 
sodium  salt.  The  presence  of  the  acetone  in  this  mixture  greatly  facilitates  the  trans- 
formation to  the  sodium  salt,  and  prevents  any  appreciable  oxidation  by  the  air.  The 
blue-green  solution  was  filtered  immediately  through  hardened  filter  paper  into  a  mixture 
of  750  cc.  of  water  and  40  cc.  of  cone,  hydrochloric  acid  The  hydroxylamine  derivative 
was  collected  and  washed  with  boiling  water;  yield,  7  g.  It  was  crystallized  from 
methanol  in  the  form  of  maroon  colored  clusters.  Yield,  6.5  g. 

Analysis.  Subs.,  0.3730:  N,  19.6  cc.  (22°,  758  mm.).  Calc.:  N,  5.87.  Found: 
5.91. 

It  is  soluble  in  most  of  the  ordinary  organic  solvents,  especially  in  hot  acetone  and 
in  hot  or  cold  pyridine. . 

The  Potassium  Salt  of  the  Hydroxylamine  Derivative 

One  g.  of  the  hydroxylamine  derivative  was  dissolved  in  a  small  amount  of  acetone. 
The  solution  was  cooled  with  ice  and  treated  with  the  calculated  amount  of  potassium 
ethylate.  The  color  of  the  solution  gradually  changed  from  red-brown  to  dark-green  and 
a  precipicate  formed.  Ether  was  added  to  precipitate  the  salt  completely,  which  was 
then  collected  on  a  filter  and  washed  with  ether.  While  the  ether  was  being  removed 
by  suction,  considerable  heat  was  evolved  as  a  result  of  the  action  of  oxygen  on  the  salt. 
The  salt  was  dark  green  when  wet,  and  became  red-brown  when  dry;  yield,  about  1.2  g. 
It  was  soluble  with  difficulty  in  warm  water,  and  more  readily  in  acetone  and  water 
forming  the  characteristic  deep  blue-green  solution.  After  exposure  of  the  solid  salt  to 
the  air  for  4  days,  no  blue-green  color  was  apparent  when  it  was  treated  with  water,  or  a 
mixture  of  acetone  and  water. 

The  remaining  material,  which  was  red-brown  in  color,  was  washed  with  hot  water 
to  remove  any  alkali.  A  sample  of  the  residue  crystallized  from  alcohol  in  the  form 

19  Barnett,  Ref.  11,  p.  192. 


1-HYDROXYLAMINO-ANTHRAQUINONE  2305 

of  old-rose  colored  needles  which  melted  at  219-221°.  This  melting  point  is  several 
degrees  lower  than  the  true  melting  point  of  1-nitroso-anthraquinone  (See  following 
preparation).  It  was  not  purified  further  because  the  sample  was  too  small.  It  gave 
Liebermann's  test  for  nitroso  compounds.  When  treated  with  hydrogen  sulfide  in 
pyridine  solution,  it  was  reconverted  to  the  hydroxylamine  derivative. 

1-Nitroso-anthraquinone,  by  the  Oxidation  of  the  Hydroxylamine  Derivative  with  Air 

Two  g.  of  the  hydroxylamine  derivative  was  dissolved  in  about  400  cc.  of  water  and 
35  cc.  of  a  1:3  solution  of  sodium  hydroxide.  The  solution  was  filtered  to  remove  any 
insoluble  material.  A  rapid  current  of  air,  free  from  carbon  dioxide,  was  passed  through 
the  filtrate.  The  color  of  the  filtrate  changed  gradually  from  deep  blue-green  to  dark 
red,  and  a  precipitate  formed.  After  no  further  change  took  place  (3-4  hours),  the  air 
stream  was  stopped  and  the  precipitate  was  collected.  It  was  a  red  powder  with  a  violet 
tinge.  It  crystallized  readily  from  alcohol,  from  benzene,  from  toluene,  and  from  chloro- 
form. It  gave  Liebermann's  nitroso  reaction  when  treated  with  phenol  and  cone,  sul- 
furic  acid.  It  was  reduced  to  the  hydroxylamine  derivative  by  treatment  with  potas- 
sium sulfide  or  hydrogen  sulfide  and  pyridine.  From  alcohol,  it  separated  in  old-rose 
colored  needles  which  melted  at  223-224°;  yield,  1  g. 

Analysis.  Subs.,  0.1915:  N,  10  cc.  (26°,  763  mm.).  Calc.:  N,  5.95.  Found: 
5.80. 

Hydrogen  peroxide  was  detected  in  the  filtrate  separated  from  the  nitroso  compound, 
by  the  action  of  a  dil.  solution  of  potassium  dichromate  upon  a  portion  of  it  acidified 
with  dil.  sulfuric  acid  and  covered  with  ether.  The  characteristic  blue  color  was  pro- 
duced in  the  ether  layer.  The  presence  of  hydrogen  peroxide  was  confirmed  also  by 
shaking  some  of  the  filtrate  with  benzoyl  chloride  until  white  crystals  separated.  When 
these  crystals  were  brought  in  contact  with  an  acid  solution  of  potassium  iodide  contain- 
ing some  starch,  iodine  was  liberated  abundantly.  This  is  characteristic  of  benzoic 
peroxide. 

The  Substituted  Urea  Derivative 

One  g.  of  finely  powdered  hydroxylamine  derivative  was  suspended  in  about  100  g. 
of  dry,  freshly  distilled  toluene  containing  0.8  g.  of  phenyl  isocyanate.  (See  p.  2302.) 
The  mixture  was  refluxed  for  about  3  hours.  The  hot  solution  was  filtered  to  separate  a 
small  amount  of  insoluble  matter  and,  as  it  cooled,  fairly  long,  dark  red-brown  needles 
formed  on  the  walls  of  the  flask.  Yield,  0.6  g.  Melting  point,  236  °. 

Analysis.  Subs.,  0.3000:  N,  22.2  cc.  (23°,  761  mm.).  Calc.:  N,  7.9.  Found: 
8.3. 

Hydrolysis  of  the  Substituted  Urea. — One  g.  of  the  urea  derivative  was  heated 
in  a  sealed  tube  for  3  hours  at  200°  with  about  50  cc.  of  cone,  hydrochloric  acid.  When 
the  tube  was  opened,  the  gas  which  escaped  produced  a  white  precipitate  with  baryta 
water;  this  proved  the  presence  of  carbon  dioxide.  The  hydrochloric  acid  solution  was 
red-brown  in  color.  It  was  made  alkaline  with  sodium  hydroxide  and  distilled  with 
steam.  The  distillate  showed  the  presence  of  aniline;  it  gave  a  dark  violet  color  with  a 
solution  of  bleaching  powder,  a  red-brown  (nearly  black)  color  with  sulfuric  acid  and 
potassium  dichromate,  and  a  white  precipitate  with  bromine  water.  This  white  pre- 
cipitate was  identified  as  .ryw-tribromo-aniline  by  crystallizing  it  from  alcohol  and 
determining  its  melting  point,  which  was  found  to  be  118-119°. 

Summary 

1.     New  methods  for  preparing  1-nitro-anthraquinone  and  1-hydroxyl- 
amino-anthraquinone  have  been  devised. 


2306 

2.  The  melting  points  of  pure   1-nitro-anthraquinone  and  of  pure 
1-amino-anthraquinone  were  found  to  be  considerably  higher  than  the 
values  given  in  the  literature. 

3.  The  properties  and  reactions  of   1-hydroxylamino-anthraquinone 
are  described. 


14  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 

LOAN  DEPT. 

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